score:13
Actually, the word Christian is used three times in the New Testament. The first occasion answers your question (Acts 11:26c):
It was at Antioch that the believers were first called Christians.
Regarding ''how'' they came to be called Christians, Wikipedia states:
Kenneth Samuel Wuest holds that all three original New Testament verses' usages reflect a derisive element in the term Christian to refer to followers of Christ who did not acknowledge the emperor of Rome. The city of Antioch, where someone gave them the name Christians, had a reputation for coming up with such nicknames
Upvote:-1
Those that believe the Book of Mormon to be the word of God, and a translation of ancient record, have reason to believe the term Christian predates New Testament times. In Alma 46:13 we find its first reference in the Book of Mormon, and an explanation of its use (my emphasis). This occurred around 73-72 BC in the Americas.
Alma 46:13-15 - 13 [Moroni prays for liberty among the people] so long as there should a band of Christians remain to possess the landβ
14 For thus were all the true believers of Christ, who belonged to the church of God, called by those who did not belong to the church.
15 And those who did belong to the church were faithful; yea, all those who were true believers in Christ took upon them, gladly, the name of Christ, or Christians as they were called, because of their belief in Christ who should come.
Interestingly enough the term seems to have a similar origin. In both cases it was used by those that did not believe in Christ to describe believers.